Light emitting devices capable of emitting visible and white light are expanding their applications to, for instance, illumination devices, display devices, and backlight sources for image display devices.
In these applications, there is a growing demand for downsizing. In this context, downsizing of electronic devices has been facilitated by an SMD (surface-mounted device) light emitting device in which a light emitting element chip is bonded onto a lead frame and molded with resin.
To replace fluorescent lamps and incandescent bulbs by illumination devices based on semiconductor light emitting devices with low power loss, it is necessary to enhance mass productivity and reduce cost.
An example technique for further downsizing is disclosed. In this example technique, a light emitting element chip is flip-chip connected to an interconnect layer provided on a transparent substrate so as to be externally driven via a columnar electrode and a ball. On the transparent substrate, the light emitting element chip and the columnar electrode are covered with a sealant.
However, this example needs the interconnect layer and the columnar electrode for bonding the light emitting element chip onto the transparent substrate with high positional accuracy, and it is insufficient to meet the requirements for downsizing and mass productivity.
Furthermore, in a fluorescent-conversion white LED (light emitting diode), wavelength conversion of excitation light by the fluorescent material cannot avoid Stokes loss in which the energy difference between the excitation light and the fluorescent-emitted light is lost as heat. Thus, efficiency improvement by controlling the fluorescent material is desired.